Trowel and guard therefor



R. ROBBINS TROWEL AND GUARD THEREFOR Sept. 13, 1960 Filed Sept. 26, 1957 //VVE/V70,Q fay F/PO55/N5 United States Patent 2,952,028 7 TROWEL AND GUARD THEREFOR Roy F. Robbins, St. Paul, Minu qassignor to Louis G'. -'Ernster, doing business asErnco Enterprises, South St. Paul, h I

Filed Sept. 26,1957, Ser. No. 686,514

7 Claims. c1; rs-235.4

The present invention relates to cement and plastering trowels. More particularly my invention concerns itself j scratched'or cut by sharp blade edges when the trowel M trowel from being inadvertently bent even when subjected'to' severe blows. Still another object hereof is to provide a guard for a rectangular trowel which protects the edges of the trowel blade from being nicked or gouged and which protects persons and objects from being is not in use. i A more specific object of my invention with the mode of protecting the shape and working sur faces of such trowels both from injury thereto and therefrom. My invention has particular reference to novel combinations comprising rectangularly shaped cement surfacing and plastering trowels and the like, with means for guarding the shape and working surfaces and edges thereof.

Cement finishing and plastering trowels generally contain a relatively thin, generally flat rectangularly shaped blade. The blade may vary in size, being often quite large, for example in the order 20 inches or more in length and four inches in width. One surface of the blade provides the working or trowelling surface of the trowel. To the other or back surface of the blade is aflixed, by rivets, a long narrow shank. The shank is positioned lengthwise of the blade centrally of the lateral or'longitudinal edges thereof. Affixed to and extending generally perpendicularly from the shank is a handle support, to which in turn is cantileverly fastened a cylindrical handle extending parallel and spaced from the back surface of the blade. The handle usually is disposed generally centrally of the ends of the trowel so the trowel will have a nice balanced feel to the journeyman usingit. Instead of a cantileverly fastened handle, some trowels have a somewhat horseshoe shaped handle aflixed at each end thereof to the back surface of the trowel.

"However, in'nearly every instance the blades of the trowels with which my invention is most particularly concerned are rectangular in shape and rather elongate, as contrasted with the well known masonry or bricklayers trowel, the blade of which is more or less'triangularly shaped. I j

Since fine finishing work is done with rectangular trowels the shape of the blade and condition of the trowelling surface thereof are of critical import. A trowel which is hit and inadvertently bent is usually irreparably ruined. The condition of the lateral edges of the blade is also very important. For example, it is highly necessary that these edges remain straight and relatively free of gouges or nicks. The working or trowel ling surface must remain smooth and true. Such surface is generally planar; however with use and wear a trowelling surface or blade becomes slightly convex with respect to the long axis thereof so that the lateral edges are slightly upwardly curved toward the handle. Indeed many journeymen feel that until the trowel takes such shape it is not properly broken in for optimum use. This convex shape that the blade surface takes has a special significance to the present invention, as will be explained shortly.

Thepresent invention is particularly concerned with providing means for protecting and guarding the shape and surfaces of a trowel. An object of my invention, therefore, is to provide, in novel combination with 'a rectangular trowel, a trowel guard made of metal or is to provide a guard for trowels which actually tends to sharpen the blade edges and thus to remove nicks therefrom contracted when the trowel was used. Yet another objectinvolves the provision of a float-trowel, or finishing trowel, and ordinary rectangular trowel combined into one. 1

The manner in which and means through which these and other objects and advantages are attained by the invention hereof will become apparent upon a consider ation of the following description including the appended claims and the drawings, in which like reference characters refer to corresponding parts in the several views and in which: i

JFigure 1' is a view in perspective of a rectangular trowel to which is removably attached in place a trowel guard of the present invention;

Figure 2 is a view in section-taken along the lines 2-2 of Figure 1 with the handle retaining shank being omitted; i.

.Figure3 is a view in perspective of a somewhat different type-of rectangular trowel removably containing a guard of the present invention to which is attached a finishing float; and

Figure 4 is a section view taken along the line 4-4 of Figure 3. a Referring now to Figures 1 and 2, a trowel containsa rectangular blade 10 to the back or non-trowelling surface of which is affixed by rivets (not shown) or other suitable means, ashank 11. The shank is somewhat shorter than the lengthwise dimension of the blade. 10 and is afiixed to the blade centrally of the lateral edges thereof. A handle support 12 extends upwardly from the shank 11 away from the blade 10. Cantileverly extending from said support 12 is a cylindrical handle 13. The handle is retained on the support 12 by virtue of a bolt which is affixed to the support and extends through handle, a nut 14 being turned on the bolt.

Disposed around the blade 10 is a trowel guard composed of relatively light-weight, -i.e. rather flexible, material, for example 26 gage (0.025 inch thick) sheet steel. The guard comprises a panel 15 of rectangular shape generally coinciding with that of the blade 10. 'In the position in which the guard is shown the panel 15 is in superposition with the blade 10Tand in contact with the trowelling surface thereof. Aifixed to each side of the panel 15 along substantially theentire length thereof are relatively narrow retaining guides 16. In the embodiment shown said guides consist. of a continuation of the panel 15, the guides having been folded over during formation of the guard. The retaining guides 16 extend around and about the laterial edge extremities of the blade 10 and over the lateral portions thereof. The respective lateral edges 17 of the blade are engaged by the retaining guides 16, which are positioned or folded back over such that they are closely adjacent the panel and thus firmly engage the blade when the latter is slid or wedged there between.

Afiixed to one end of the panel 15 and folded over the end of blade 10 adjacent said end is a narrow stop member 18. stop member is folded over much A further object is the of the guides 16 adjacent the stop member 18 and each corner of stop member is cut off approximately at a 45 degree angle. In this manner they will closely fit together in abutting relationship. If desired the seam where these members abut may be welded, but this is not essential.

The end of the guard opposite the forward end 18 is not provided with any member which will obstruct passage of the trowel blade as the trowel is slid into and from the guard. As will be appreciated the retaining guides 16 and the stop member 19 are folded over in closely spaced relation to the inner surface of the panel 15. In fact, when the trowel is not in position in the guard, some portions of these may be in contact with the panel 15. When the trowel is slid or pushed into position, being guided into place along the sides by the retaining guides 16 and prevented from passing too far by stop member 15, the spring-like nature of the metal, or other suitable material yields to the wedging action of the blade 10. The latter thus is held firmly in place.

As can be seen the retaining members 16 and the'stop member 19 are each sufiiciently narrow as to terminate laterally short of so as not to catch or collide with the shank 11 or handle 13 as the trowel :is slid to or from its position in the guard.

Since the guard is preferably composed of a flexible rather light-weight gage of sheet material it might be expected that it would not adequately protect the blade from being bent. However the rib formed at the juncture of the panel 10 with the retaining guides 16 and stop member 18 adequately reinforces the guard in directions parallel with the edges thereof. By itself guard may, however, still seem unduly flexible and distortable in the diagonal directions. I have found this to be of little import. For in my novel guard and trowel combination, when the trowel is in place, the shank and/or handle means extending lengthwise of the blade reinforces the guard in the diagonal direction and the guard in turn reinforces the blade throughout. This mutual reinforcing action between guard and blade, ultimately to protect the blade, is believed to be one of the unique features of my invention.

In retaining the trowel in place the retaining guides 16 may bear against either the extreme edges of the blade 10, or they may bear against the lateral edge portions of the back surfaces of the blade, or they may bear against both. However, as noted previously, a properly broken in trowel generally has somewhat of a convex trowelling surface, such as can be seen from Figure 2. In such case invariably the lateral edges 17 of the trowel contact the inside surfaces of the retaining guides 16. I have found that as the trowel is slid into and from the guard the bearing of these against the edges of the blade tends to abrade the edges and eliminate tiny scratches or nicks that may have been contracted when the trowel was in use. This is particularly true where the inner surface of the retaining guides are treated or provided with an abrasive surface, such as a strip coated abrasive sheet, with abrasive particles adhered to the guide surface with a binder, etc. Or the surface of the retaining guide may be roughened or inherently be of a quality such that an abrasive action is provided when the blade passes againsst the retaining guide surfaces.

Referring now to Figures 3 and 4 a slightly different form of my invention will be seen. The trowel is similar to that shown in Figure l and contains a rectangular blade 3 b t is Provided with h s tl e eh adle. 3.

4 The handle 31 is aflixed to the blade 30 (by means not shown) at its ends 33. The guard is similar to that described above having a panel 35, retaining guides 36 and a stop member 37. However a resilient flat section 38, composed, for example, of a sponge rubber cut to a rectangular shape the size of the panel 35, is adhered to the panel 35 with a suitable adhesive. Thus is provided a finishing float having distinct advantages. For

' instance the same member that serves as the support for the float can be, when the float and guard are removed therefrom, used as a trowel. Thus is combined is combined a trowel and float into one. Further, when the resilient float has been worn out it is unnecessary to throw away the trowel or support, this being the most expensive item Otf the combination. Rather, only the guard and float, or perhaps only the float need be replaced. Further, when the trowel is not in use the guard-float effectively series to protect the trowel from damage and from causing injury and damage. Of course the material of which the float is formed can be of any suitable composition such as wood, cork, rubber, plastic, etc., as the use for the float dictates.

Having now described my invention by reference to specific illustrative embodiments, various equivalents undoubtedly become apparent to the artisan. However, it is not my intention to be limited to the specific embodiments shown, but rather only by the specification taken as a whole including the appended claims.

What I claim is as follows:

1. In combination with a trowel having a generally rectangular blade the lateral edges of which are curved slightly upwardly toward the direction of its back surface and a handle retaining shank affixed to the back surface of said blade and extending lengthwise of said blade centrally of the side edges thereof, a guard comprising a relatively thin panel of rectangular shape coextending with said blade and having opposed parallel sides and opposed parallel ends extending perpendicularly with respect to the sides, said panel being in contact and generally in superposition with the trowelling surface of said blade, a relatively narrow retaining guide aflixed along substantially the entire length of each of said sides and extending about the lateral edges of said blade and over the lateral portions of said back surface, the inner surfaces of said retaining guides each having an abrasive surface with said surfaces bearing against and yieldably and slidably engaging the lateral edges of said blade with the laterally inward edges of said guides terminating short of the handle and shank, and a relatively narrow stop member aifixed along one end of said panel and extending about the end edge of said blade over and in slidable contact with said back surface, the edge of said panel opposite said one end being free of obstruction to permit said blade to he slid into and from said guard.

2. In combination with a trowel having a generally rectangular blade the lateral edges of which are curved slightly upwardly toward the direction of its back sur face and a handle aflixed to the back surface of said blade, a guard comprising a relatively thin panel of rectangular shape coextending with said blade and having opposed parallel sides and opposed parallel ends extending perpendicularly with respect to the sides, said panel being in contact and generally in superposition with the trowelling surface of said blade, a relatively narrow retaining guide aflixed along substantially the entire length of each of said sides and extending about the lateral edges of said blade and over the lateral portions of said back surface, said retaining guides bearing against and yieldably and slidably engaging and inducing a sharpening action on the lateral edges of said blade with the laterally inward edges of said guides terminating short of the handle, and a relatively narrow stop member afiixed alongone end of said panel and extending about the end edsa fsaidblade ov rardrin lidable on act t said back surface, the edge of said panel opposite said one end being free of obstruction to permit said blade to he slid into and from said guard.

3. A guard for a trowel having a rectangular blade and handle means affixed to the back surface of said blade generally centrally thereof, the surface of said blade opposite said back surface defining a trowelling surface, said guard comprising a relatively thin panel of rectangular shape coextending with said blade and having opposed parallel sides and opposed parallel ends extending perpendicularly with respect to the sides, a relatively narrow retaining guide afiixed along substantially the entire length of each of said sides and extending over respective lateral portions of one surface of said panel in closely spaced relation therewith, whereby said blade with said handle passing between and free of the inward extremities of said retaining guides can be slid between the said panel and said retaining guides with the latter engaging the edges of said blade, the inner surfaces of said guides which engage said edges being of a character to induce a sharpening action on said edges, and a relatively narrow stop member aflixed along one of said ends and extending over an end portion of said one surface in closely spaced relation therewith to engage said blade when said blade passes between it and said one surface, the end of said panel opposite said one end being free of obstruction to permit said blade to be slid into and from said guard.

4. A guard for a trowel having a flat rectangular blade and handle means afiixed to the back surface of said blade generally centrally thereof, the surface of said blade opposite said back surface defining a trowelling surface, said guard comprising a relatively thin panel of rectangular shape coextending with said blade and having opposed parallel sides and opposed parallel ends extending perpendicularly with respect to the sides, a relatively narrow retaining guide affixed along substantially the entire length of each of said sides and extending over respective lateral portions of one surface of said panel in closely spaced relation therewith, the inner surfaces of said retaining guides having abrasive surfaces whereby said blade with said handle passing between and free of the inward extremities of said retaining guides can be slid between the said panel and said retaining guides with the said abrasive surfaces engaging the edges of said blade, and a relatively narrow stop member afiixed along one of said ends and extending over an end portion of said one surface in closely spaced relation therewith to engage said blade when said blade passes between it and said one surface, the end of said panel opposite said one end being free of obstruction to permit said blade to be slid into and from said guard.

5. In combination with a trowel having a generally rectangular blade the lateral edges of which are curved slightly upwardly toward the direction of its back surface and a handle afiixed to the back surface of said blade, a float containing guard comprising a relatively thin panel of rectangular shape coextending with said blade and having opposed parallel sides and opposed parallel ends extending perpendicularly with respect to the sides, said panel being in contact and generally in superposition with the trowelling surface of said blade, a float aflixed to the surface of said panel not in contact with said blade, a relatively narrow retaining guide aflixed along substantially the entire length of each of said sides and extending about the lateral edges of said blade and over the lateral portions of said back surface, said retaining guides bearing against and yieldably and slidably engaging and inducing a sharpening action on the lateral edges of said blade with the laterally inward and a relatively narrow stop member aflixed along one 6 end of said panel and extending about the end edge of said blade over and in slidable contact with said back surface, the edge of said panel opposite said one end being free of obstruction to permit said blade to he slid into and from said guard.

6. A float containing guard for a trowel having a generally rectangular blade and handle means aflixed to the back surface of said blade generally centrally thereof, the surface of said blade opposite said back surface defining a trowelling surface, said guard comprising a relatively thin panel of rectangular shape coextending with said blade and having opposed parallel sides and opposed parallel ends extending perpendicularly with respect to the sides, a relatively narrow retaining guide afiixed along substantially the entire length of each of said sides and extending over respective lateral portions of one surface of said panel in closely spaced relation therewith, whereby said blade with said handle passing between and free of the inward extremities of said retaining guides can be slid between the said panel and said retaining guides with the latter engaging the edges of said blade, the inner surfaces of said guides which engage said edges being of a character to induce a sharpening action on said edges, a float aflixed to the surface of said panel opposite said one surface, and a relatively narrow stop member affixed along one of said ends and extending over an end portion of said one surface in closely spaced relation therewith to engage said blade when said blade passes between it and said one surface, the end of said panel opposite said one end being free of obstruction to permit said blade to he slid into and from said guard.

7. In combination with a trowel having a generally rectangular blade the lateral edges of which are curved slightly upwardly toward the direction of its back surface and a handle affixed to the back surface of said blade and extending lengthwise of said blade, a float containing guard comprising a relatively thin panel of rectangular shape coextending with said blade and having opposed parallel sides and opposed parallel ends extending perpendicularly with respect to the sides, said panel being in contact and generally in super-position with the trowelling surface of said blade, a float aflixed to the surface of said panel not in contact with said blade, a relatively narrow retaining guide aflixed along substantially the entire length of each of said sides and extending about the lateral edges of said blade and over the lateral portions of said back surface, the inner surfaces of said retaining guides each having an abrasive surface with said surfaces bearing against and yieldably and slidably engaging the lateral edges of said blade with the laterally inward edges of said guides terminating short of the handle and shank, and a relatively narrow stop member affixed along one end of said panel and extending about the end edge of said blade over and in slidable contact with said back surface, the edge of said panel opposite said one end being free of obstruction to permit said blade to he slid into and from said guard.

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